Semiconductor devices are widely used in various electronic equipment, such as smart phones, laptops, digital cameras, and other equipment. In general, a typical semiconductor device includes a substrate having active devices such as transistors, capacitors, inductors and other components. These active devices are initially isolated from each other, and interconnect structures are subsequently formed over the active devices to create functional circuits. Such interconnect structures may include lateral interconnections, such as metal lines (wirings), and vertical interconnections, such as conductive vias or contact plugs.
There is an ever increasing demand for smaller and faster semiconductor devices which are simultaneously able to support a greater number of increasingly complex and sophisticated functions. This scaling down process generally provides benefits by increasing production efficiency and lowering associated costs. Nevertheless, such scaling down has also increased the complexity of processing and manufacturing of the semiconductor devices. As dimensions of semiconductor devices scale to smaller sub-micron sizes in advanced technology nodes, it becomes an increasing challenge to reduce the interconnect structure resistance while decreasing the interconnect structure size. Improved structures and methods for manufacturing same are needed.